ИСТИНА

Performance errors in visual tasks caused by deterioration of the cognitive control may be related to an increase in the alpha-band power (for example, O'Connel et al., 2009), although this effect has not been studied within the auditory modality. In order to investigate EEG predecessors of attentional lapses in the auditory modality we used the modified condensation task. Participants (N=47) were presented with four auditory tones, each having two distinct features: "low" or "high" (500 Hz or 2000 Hz sinusoidal signal), "noised" or "pure" (with or without broadband noise admixed). Participants were asked to press one or the other button depending on the conjunction of the two features. Frequent distractors (pure 400 Hz tones) were also presented along with four target stimuli. Prestimulus EEG power in the alpha range (8-13 Hz) was found to be reduced for erroneous responses compared with correct responses. Prestimulus alpha-band power gradually increased within continuous sequences of distractor stimuli separating adjacent target stimuli. No performance–related changes in stimulus-locked ERPs were found. These findings demonstrate that under conditions of the auditory attentional task higher alpha-band power may be an index of increased rather than decreased level of cognitive control. This finding also points to the prestimulus EEG power as a better predictor of behavioral outcome compared with the stimulus-locked ERPs.